1. Field of the Invention
The present invention relates generally to accessories for hand-held power drills, and more particularly, to a leveling mechanism for drilling a hole along a horizontal or vertical axis.
2. Description of the Prior Art
In using a hand-held power drill, it is often necessary to drill a hole having a horizontal or vertical axis. Various mechanisms for use in conjunction with hand-held power drills are well known in the art for aiding the operator in guiding the drill bit in a horizontal or vertical manner. Often, the work surface into which the hole is to be drilled is itself disposed vertically or horizontally, and the drill bit need only be maintained perpendicular to the work surface. Prior art devices are known for maintaining the drill bit perpendicular to the work surface. One such prior art device is a drill guide of the type commercially available from Portalign Tool Corporation of San Diego, Calif. under the registered trademark "PORTALIGN". The drill guide includes a base for resting against the work surface, a pair of guide rods extending upwardly from the base, and an adaptor which slidingly engages the guide rods. The adaptor is attached to the drive shaft of the drill for guiding the drill bit perpendicular to the work surface. However, the base of the drill guide tends to obscure the work area during drilling, often making drilling more difficult. In addition, such drill guides are not easily used to drill a horizontal or vertical hole if the work surface is not itself vertically or horizontally disposed.
Other types of drill guides which are adapted to rest against the work surface but attach to the drill housing rather than to the drive shaft of the drill are also known. For example, a drill guide available from Black & Decker, Inc. of Towson, Md., under the trademark "GUIDEMATE", includes a track which can be supported perpendicular to the work surface and a carrier which slides within the track. The carrier is clamped to the drill housing for guiding movement of the drill along the track. This type of drill guide has less of a tendency to obscure the work area during drilling. However, because the drill guide is attached to the drill housing rather than to the drive shaft of the drill, proper alignment between the drilling axis and the drill guide is difficult to achieve. This difficulty in achieving proper alignment is aggravated by the variety of drill housing contours utilized by the various manufacturers of hand-held power drills now available.
Other prior art devices are also known wherein bubble levels are utilized in conjunction with a hand-held power drill for allowing a hole to be drilled along a horizontal or vertical axis. Often, the bubble levels are removably attached to the outer periphery of the drill housing or handle without requiring modification of the drill itself. U.S. Pat. Nos. 4,154,001 (Serafin), 4,141,151 (Jansky), and 2,768,483 (Sauer, Jr.) each disclose a bubble level mechanism which is clamped to the drill housing or handle by a band or bracket. However, drill housings often lack planar surfaces that are perfectly parallel or perpendicular to the drilling axis for supporting such bubble level mechanisms. Accordingly, these prior art devices must be carefully adjusted and positioned prior to use in order to properly align the bubble level with the drilling axis. For example, in the above-identified patent to Sauer, Jr., the leveling mechanism disclosed therein is provided with a plurality of adjusting screws for aligning the plane of the bubble level relative to the drilling axis. Similarly, in the above-identified patent to Serafin, a foot positioning device must be inserted within the chuck of the drill to properly position the leveling mechanism relative to the drilling axis before the hole can be drilled. Moreover, leveling mechanisms of the type which are removably attached to the drill housing typically require readjustment each time the leveling mechanism is removed and subsequently reattached to the drill housing.
Prior art leveling mechanisms of the type disclosed by the above-identified patent to Serafin include a bubble level which can be positioned at various angles relative to the drilling axis. However, each time that the angular relationship between the bubble level and the drilling axis is changed, the position of the bubble level must be carefully readjusted. Typically, the operator would need to reinsert the foot positioning device within the chuck to readjust the position of the bubble level. It is therefore difficult to accurately and repeatedly alternate the position of the bubble level from among various desired angular relationship with the drilling axis.
Also disclosed in the prior art are drills which have been modified to incorporate bubble levels therein. For example, U.S. Pat. Nos. 3,864,839 (Wolf), and 3,664,754 (Kelbel) each disclose such a drill. However, drills of the type disclosed in the above-identified patents must be substantially modified from hand-held power drills of the type generally available because the drill housings of conventional drills often lack planar surfaces that are perfectly parallel or perpendicular to the drilling axis and against which such bubble levels may be supported.
Accordingly, it is an object of the present invention to provide a leveling mechanism for use in conjunction with virtually any conventional hand-held power drill wherein the leveling mechanism is readily attachable to and removable from the drill, and wherein proper alignment of the leveling mechanism with the drilling axis is ensured upon attachment of the leveling mechanism to the drill.
It is another object of the present invention to provide a leveling mechanism for use in conjunction with a hand-held power drill wherein the leveling mechanism does not obscure the work surface into which the hole is to be drilled.
It is a further object of the present invention to provide a drill having a housing particularly adapted to engage a removable leveling mechanism.
It is still a further object of the present invention to provide a leveling mechanism for use in conjunction with a hand-held power drill wherein the leveling mechanism can be accurately and repeatedly positioned at a plurality of predetermined angular relationships to the drilling axis.
These and other objects of the present invention will become apparent to those skilled in the art as the description thereof proceeds.